Dynamic threshold 1b questions

[Daniel James White]

Hi all,

I am making teaching material and practical demos
for an image processing course,
and want to show local adaptive thresholding.

so i started looking at the plugin
DynamicThreshold1b

I run the plugin on a sample image
of a 256 square with a linear 0-255 gradient left to right,
with a 87 grey level intensity blob in the middle of it.

The plan is to segment out the blob from the non flat background.

Can anyone tell me why all of the different out put images
contain pixel values other than 0 and 255?

As I read teh documentation at
http://homepages.inf.ed.ac.uk/rbf/HIPR2/adpthrsh.htm

the output for median,mean, max min, and (max+min)/2
  methods should give only binary images?

I see the dialog box to change the neighbourhood size,
but there is no way to change the C value
as described on the webpage above?

Anyone have any ideas there?
Or know of an adaptive local threshold plugin that gives binary images  
as the output?

ImageJ 1.39d
with MacbioPhotonics and other plugins installed.
OSX 10.5

cheers

Dan


Dr. Daniel James White BSc. (Hons.) PhD
Senior Microscopist / Image Processing and Analysis
Light Microscopy Facility
Max Planck Institute of Molecular Cell Biology and Genetics
Pfotenhauerstrasse 108
01307 DRESDEN
Germany


New Mobile Number!!!

[phone] (German Mobile)
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[Joachim Wesner]

Hi Daniel,

I could take a look what is going on, but that certain

DynamicThreshold1b

plugin you are referring too, where did you get it from? It does not seem
to be part of the official distribution nor is on the plugin website!!??

(Seems to be part of that MacBio.... distribution?)

Joachim

ImageJ Interest Group <[hidden email]> schrieb am 15.04.2008 18:17:20:

> Hi all,
>
> I am making teaching material and practical demos
> for an image processing course,
> and want to show local adaptive thresholding.
>
> so i started looking at the plugin
> DynamicThreshold1b
>
> I run the plugin on a sample image
> of a 256 square with a linear 0-255 gradient left to right,
> with a 87 grey level intensity blob in the middle of it.
>
> The plan is to segment out the blob from the non flat background.
>
> Can anyone tell me why all of the different out put images
> contain pixel values other than 0 and 255?
>

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